The present invention relates to an electrical extension lead arrangement or adapter comprising a plug, at least one socket, and an extension lead connecting the or each socket to the plug.
Electrical extension leads and adapters comprising extension leads with plugs and sockets are known. These are typically bulky. Such extension lead arrangements and adapters are perfectly suitable for occasional domestic or industrial use, where space is not a problem. However, such arrangements or devices are not particularly suitable for, for example, travel and they are not easily portable or particularly discrete.
The present invention aims to provide an extension lead arrangement or electrical adapter which is light and compact and, therefore, relatively easily portable and which is also safe to use.
According to a first aspect, therefore, the present invention provides an electrical extension lead arrangement comprising a plug, a socket and an electrical lead connecting the socket to the plug, wherein the socket is provided in a body around which the electrical lead is windable, characterised in that unless the electrical lead is fully unwound from the body, no electrical connection can be made between a connector pin and the socket.
The present invention in a preferred embodiment relates to an electrical adapter comprising a plug, a socket, and an extension lead connecting the socket to the plug, in which the socket is disposed in a body around which the extension lead is windable such that while the lead is at least partially wound, insertion is prevented of a pin of a connector in a hole of said socket so as to prevent electrical connection to the connector.
This advantageously avoids the risk of excessive heating of the extension lead. Such excessive heating can occur in prior art leads or adapters which are usable with their extension leads wound.
Preferably the pin of a connector is prevented from being inserted in the hole of the socket by abutment of the pin with the extension lead prior to full insertion. Alternatively the socket can be provided with a shutter, the shutter being movable to an open position by unwinding the extension lead. The shutter can be held in its closed position by the wound or partially wound extension lead, and can be spring-biased to its open position when the extension lead is unwound.
The invention in its second aspect relates to an electrical adapter comprising a plug, a socket, an extension lead connecting the socket to the plug, a body around which the extension lead is windable, the body comprising two end plates, characterised in that the plug comprises means for cooperative engagement with at least one of the end plates. The plug preferably clip-fits over or between peripheral lips provided on each end plate.
In a preferred embodiment, this advantageously provides an electrical adapter which is compact and in which the plug is attached to the body so as to prevent the lead unwinding during transport and storage.
Preferably, the means for cooperative engagement comprises a groove. The groove preferably comprises opposing side walls, each lip engaging with a corresponding one of the side walls.
Preferably, the lips have outwardly projecting lands and the corresponding side walls have inwardly projecting lands, such that when the plug is clip-fitted, the lands cooperate to hold the plug in place on the body.
Preferably upon the lead being at least partially wound, insertion of a pin of a connector in a hole of the or each socket is prevented so as to prevent electrical connection to the connector.
The electrical extension lead arrangement or adapter can preferably include a second adapter also having a groove for cooperative engagement with the lips. The second adapter can preferably be a housing for a socket on which plug pins are mounted.
The present invention in its third aspect relates to an electrical extension lead arrangement or adapter according to the present invention in its first aspect and in its second aspect.
The plug can be a UK standard plug, such as a 13 amp plug, or can be a plug of any other type, such as in accordance with U.S. and/or European standards. The or each socket can be a UK standard socket, such as a 13 amp socket, or a socket of any other type, such as in accordance with U.S. and/or European standards.
The device preferably comprises two sockets. The two sockets are preferably positioned with their socket holes at opposite ends of the body. Preferably the live contacts of the sockets are adjacent, and the neutral contacts of the sockets are adjacent, for ease of interconnection.
An earth contact can be provided on the body for connection in use to an earth pin of a UK standard plug inserted into one of the sockets, with the earth contact being connected via the extension lead to the plug.
In accordance with a further aspect of the invention, there is provided an electrical extension lead arrangement comprising a plug, two sockets and an electrical lead connecting the sockets to the plug, wherein the sockets are provided in opposing end surfaces of a body around which the electrical lead is windable, and wherein the sockets are arranged such that the holes of the sockets provided in one end surface of the body are located at the same positions on the end surface as the corresponding holes of the other socket in the other end surface.
This particular feature provides an electrical extension lead or an adapter which is particularly compact. A single contact strip or wire can be provided between the corresponding holes of the two sockets.